In recent years, a technique of selectively etching one of a SiGe and a Si with respect to the other in the target substrate where the SiGe and the Si coexist is required. As an example, there is provided a technique of selectively side-etching one of a Si and a SiGe with respect to the other in a target substrate that has a laminated structure of the Si and the SiGe.
To meet the requirements, as a technique of selectively etching a SiGe with respect to a Si, there are known a technique of performing the selective etching by using ClF3 and XeF2 as an etching gas and another technique of performing the selective etching by using HF as an etching gas. Further, as a technique of selectively etching a Si with respect to a SiGe, there is known a technique of performing the selective etching by using an etching gas including SF6 and CF4 to which a germanium-containing gas is added.
In the aforementioned techniques, either selectively etching the SiGe with respect to the Si or selectively etching the Si with respect to the SiGe is performed. However, it is required that both of selectively etching the SiGe with respect to the Si and selectively etching the Si with respect to the SiGe be performed in the same apparatus using the same gas system.